A NEW SPOEOZOON IN AMPHIOXUS. 315 



Whether this be so or not, a brief description of this 

 Protozoan may not be without interest, no parasite having 

 been previously described in Amphioxus. 



This member of the Ciliata is one of the Aspirotrichous 

 Trichostomata, varying in length from -4 to '7 ram. There 

 is a definite mouth and short pharynx in a lateral position 

 (fig. 10, a, 0). A large nucleus is situated more or less pos- 

 teriorly, and is not unfrequently lobed in a curious fashion 

 (fig. 10, c), an appearance which is, however, probably due to 

 shrinkage, since it is not of invariable occurrence. 



The cell protoplasm is very granular, the granules some- 

 times, as in fig. 10, c?, being extremely large. 



These parasites occur in considerable numbers, and are 

 found in the atrium both anterior and posterior to the atrio- 

 pore. 



